A seizure of methamphetamine consists of 100 packets of the powder. The percent purity of each is shown in the accompanying table, although the analysts do not know these concentrations at the start of the analysis. After proving that all 100 contain methamphetamine, they select each packet with a number divisible by 10 (#10, #20, etc.) and perform a quantitative analysis. Assuming the laboratory results closely approximate the true values, answer the following: (a) What type of sampling is this? (b) Assume that rather than selecting 10% of the seizure for testing, they elected to use the hypergeometric mean as a starting point. How many samples are needed for 95% confidence that 90% of the samples are methamphetamine? (c) How would you suggest the analysts select these samples